(a) Field
Embodiments of the present invention relate to an organic light emitting diode (OLED) display. More particularly, embodiments of the present invention relate to an OLED display having stabilized luminescence characteristics.
(b) Description of the Related Art
Unlike the liquid crystal display (LCD), an organic light emitting diode (OLED) display does not use a separate light source, thereby making it possible to be implemented as a slim and lightweight display. Furthermore, as the organic light emitting diode display has high quality characteristics such as lower power consumption, high luminance, and fast response time, it has been considered as a next generation display device.
The OLED includes a plurality of light emitting diodes each having a hole injection electrode, an organic emission layer, and an electron injection electrode. Electrons and holes are combined with each other in an organic emissive layer to thereby generate excitons. When the excitons shift from the excited state to the ground state, energy is generated so as to emit light, and images are displayed using the emitted light. In this case, the organic light emitting element (e.g., an organic light emitting diode) receives a driving current from a driving thin film transistor.
However, the organic light emitting element may emit light caused by a leakage current while the driving thin film transistor is in the turn-off state. That is, the organic light emitting element emits light in a black mode caused by the leakage current so that a contrast ratio of the OLED display may be deteriorated.
In addition, undesirable light emission of the organic light emitting element due to the leakage current may reduce the life-span of the organic light emitting element.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.